Continuous Subjective Workload Assessment Technique

Despite the wide usage of the Subjective Workload Assessment Technique (SWAT), it has two main problems: it is not so sensitive at low mental workload and it requires a card sorting procedure that is time consuming. This paper suggests improvements to the original SWAT scale. The card sorting procedure has been replaced by a pair-wise comparison procedure similar to that of the National Aeronautics and Space Administration - Task Load Index (NASA-TLX). In addition, a continuous scale is used instead of the discrete SWAT scale. This Continuous SWAT scale (C-SWAT) has been compared experimentally with the original SWAT scale using simple arithmetic tasks. Results show that the "new" procedure takes significantly less time than the original card sorting procedure. The results also seem to indicate that C-SWAT is sensitive at low mental workloads. At medium mental workloads, the SWAT and C-SWAT scales give similar results.